Therapeutic benefits of a soy protein rich diet in the prevention and treatment of nephropathy in young persons with type I, insulin-dependent, diabetes mellitus

Introduction. Diabetic nephropathy is the most frequent cause of end-stage renal disease in the industrialized world. Dietary intake, including protein amount and quality, seems to affect the progression of renal disease. The hypothesis is submitted that substitution of soy protein for animal protein in the diet of Type 1 diabetes patients with incipient nephropathy will reduce abnormally high glomerular filtration rate (GFR), correct microalbuminuria, and improve serum lipid profile. These changes are interpreted as beneficial in the prevention and treatment of early stage diabetic nephropathy.; Methods. Fourteen Type 1 diabetic patients (age 29.9 ± 2.4 years, duration of diabetes 15.1 ± 2.3 years) under fairly good glycemic control were studied. Twelve of the subjects were hyperfiltering (GFR > 120 ml/min/1.73m2) and three participants had microalbuminuria (urine albumin:creatinine 20–200 mg/g). Following a four-week Run-In period to assess baseline dietary habits and laboratory values, subjects were instructed to substitute 45–55 grams of soy protein for 45–55 grams of animal protein in their diet for eight weeks (Soy Diet) followed by an additional eight weeks of their routine diet (Control Diet).; Results. GFR was significantly (p < 0.02) reduced after eight weeks of the Soy Diet (143 ± 7.4 ml/min/1.73m2) as compared to Baseline (159 ± 7.7 ml/min/1.73m2) and the Control Diet (161 ± 10.0 ml/min/1.73m2). Total and LDL-cholesterol were also significantly reduced by 7% and 9%, respectively, during the Soy Diet. Urine creatinine excretion was stable throughout the study while sodium excretion was slightly reduced during both the Soy Diet (8.00 ± 1.61 mEq/hr) and Control Diet (7.63 ± 1.59 mEq/hr) as compared to Baseline (9.20 ± 1.46 mEq/hr). In addition, two of the three subjects with microalbuminuria experienced lower albuminuria during the Soy Diet. Dietary protein intake was the same at Baseline (1.30 ± 0.12 g/kgbw/day) and during the Soy Diet (1.34 ± 0.11 g/kgbw/day), but was significantly reduced during the Control Diet (1.08 ± 0.10 g/kgbw/day).; Conclusions. Incorporation of soy foods into the diet of Type 1 diabetes patients with early diabetic nephropathy is well-tolerated and appears to have beneficial effects on GFR and lipid profile.